User login

Light Reallocation for High Contrast Projection Using an Analog Micromirror Array

Publication Type:

Journal Article


ACM Transactions on Graphics, ACM Press, Volume 29, Issue 6, no. 165 (10 pages) (2010)



high dynamic range; projection; contrast


We demonstrate a proof of concept projector with a secondary array of individually controllable analog micromirrors added to improve the contrast and peak brightness of conventional projectors. The micromirrors reallocate the light from the projector lamp away from the dark parts of the image towards the light parts, before the light reaches the primary image modulator. Each element of the analog micromirror array can be tipped/tilted to divert portions of the light from the lamp in two dimensions. By directing these mirrors on an image-dependent basis, we can increase both the peak
intensity of the projected image as well as its contrast.
In this paper, we describe and analyze the optical design for projectors using this light reallocation approach. We also discuss software algorithms to compute the best light reallocation pattern for a given input image, using the constraints of real hardware. We perform extensive simulations of this process to evaluate image quality and
performance characteristics of this process. Finally, we present a first proof-of-concept implementation of this approach using a prototype analog micromirror device.

Faculty Member(s): 
Research Area(s): 
Sensors and Actuators
Research Area(s): 
Photonics and Optics